title: Membrane stress causes inhibition of water channels in brush border membrane vesicles from kidney proximal tubule.
abstract: Brush border membrane vesicles (BBMV) from rabbit kidney proximal tubule cells, prepared with different internal solute concentrations (cellobiose buffer 13, 18 or 85 mosM) developed an hydrostatic pressure difference across the membrane of 18.7 mosM, that causes a membrane tension close to 5 x 10(-5) N cm-1. When subjected to several hypertonic osmotic shocks an initial delay of osmotic shrinkage (a lag time), corresponding to a very small change in initial volume was apparent. This initial osmotic response, which is significantly retarded, was correlated with the initial period of elevated membrane tension, suggesting that the water permeability coefficient is inhibited by membrane stress. We speculate that this inhibition may serve to regulate cell volume in the proximal tubule.
authors.affiliation: Departemento de Química (and Centro de Química Fina e Biotecnologia-CQFB), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Monte da Caparica.
authors.forename: G
authors.initials: G
authors.lastname: Soveral
authors.forename: R I
authors.initials: RI
authors.lastname: Macey
authors.forename: T F
authors.initials: TF
authors.lastname: Moura
mesh_terms: D000818:Animals; D051398:Aquaporin 1; D020346:Aquaporins; D002462:Cell Membrane / Q000502:physiology; D006874:Hydrostatic Pressure; D007473:Ion Channels / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008871:Microvilli / Q000737:chemistry / Q000378:metabolism; D009995:Osmosis; D011817:Rabbits; D013314:Stress, Mechanical; D014867:Water / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D020346:Aquaporins; D007473:Ion Channels; D014867:Water; D051398:Aquaporin 1